1. Field of the Invention
This invention relates to a process for removing helium and other impurities from a mixture containing deuterium and tritium, and a deuterium/tritium mixture when purified in accordance with such a process, and, more particularly, to a process for the processing of spent plasma removed from a fusion reactor.
The process of this invention is applicable to a plasma formed by mixtures of deuterium and tritium contaminated by the helium produced by the following fusion reaction: EQU D+T.fwdarw.He.sup.4 +neutron
Other impurities are probably present in the plasma such as CO, CO.sub.2, N.sub.2, NO, NO.sub.2, N(D,T).sub.3, C(D,T).sub.4, C.sub.2 (D,T).sub.6 having a very small concentration of about 2-3%. Even protium is expected to be present at a concentration of less than 1%.
All these impurities originate from many factors, of which the major ones are material degassing phenomena and the air infiltration even if in microquantities.
2. Description of the Prior Art
The prior art is replete with disclosures relating to the treatment of deuterium and tritium containing the above-mentioned impurities which are expected to accumulate in a real fusion burn. In the known processing design for such a fuel cycle, it is assumed to make recourse to extremely costly and very advanced procedures such as selective impurities cryogenic separation and hydrogen isotopes cryogenic distillation.
The overall dimension of these units and the other ones related to the process require a large facility for their containment.
Moreover for safety rules it is a compulsory requirement to have an emergency tritium clean-up system, in case of accident.
For this reaction, large investments and high running costs are demanded in order to maintain tritium release into the atmosphere below the present levels which are becoming more and more strict.